Hi everyone!
I have a few questions regarding different methods of doing things in pyro, and I'm not sure whats the “best” way to go about them…

first, is there a real difference between unpack and convert nodes? they seem to do the same thing, is there a preference to using one over the other?

when adding wind to pyro, its possible to do this in a few ways, all generating different results:
there is the gas wind node, pop force and pop wind, custom velocity fields, and a gas field wrangle? what do you prefer to use? and what gives a more natural movement?

for collision interactions, do you usually use “extrapolate into collisions” and “correct collisions” off? or is it more a matter of the type of look your after?

would be great to iron out these questions, as they were nagging me for a while now

Guy Tourgeman
first, is there a real difference between unpack and convert nodes? they seem to do the same thing, is there a preference to using one over the other?

Unpack and convert are completely different nodes that do unrelated things. One takes the geometry that exists as a reference, and dereferences it one or more levels; if dereferenced completely, it creates live working geometry. Convert takes one type of geometry and tries to make it into another. A convert might seem superficially like it is the same as unpacking because you might end up with polygons at the end with either node, but that is only true for a specific input and specific settings on the convert sop. Specifically polygons that are packed one level deep, and the default of convert to polys on the convert sop. If non-polygons are packed, the unpack sop will unpack to the original packed geometry type (such as tube, sphere, polysoup, packed prim, etc), while the convert will only convert to one type of geometry, such as polygons.

Guy Tourgeman
when adding wind to pyro, its possible to do this in a few ways, all generating different results:
there is the gas wind node, pop force and pop wind, custom velocity fields, and a gas field wrangle? what do you prefer to use? and what gives a more natural movement?

I'll use gas windo or gas field wrangle/vop or wind tunnel (background value of vel field.) Which I use depends on what I am after.

Guy Tourgeman
for collision interactions, do you usually use “extrapolate into collisions” and “correct collisions” off? or is it more a matter of the type of look your after?

I only mess with these to fix specific artifacts that may develop, such as gaps.

I understand, I guess I always only needed to convert the packed geo to polys so I didn't notice the difference…

what is the wind tunnel? never saw any information/tutorial about this

Some more questions, probably better to keep in all in here rather than opening a new topic

Found the wind tunnel, it produces very nice results

Is there no way to have fuel burn rate go higher than 1? from my understanding this “1” represents 1 second, what if I want my fuel to burn faster than 24 frames(for example)

When working on a Houdini scene with many different sims in it, do you usually prefer to split the hip files to a few smaller ones each for a specific element? or have it all in 1 big file? how does this affect the performance of Houdini?

Is there a way to source a few colors into smoke at the beginning of a sim? and how do I export this color to be used in a renderer such as Arnold